Acid dye



,5, compound, an azo dye "which isobtainable by Patented Aug. 13, 1935Werner many, assngnor to General Aniline Works, Inc.,' New York, N. Y.,a corporation of -Delaware No Drawing; Application April 25,, 1933,Serial solt waa I G efi q nb 25 1 claims. loam-9n The present inventionrela tes to the manufac ture of valuable dyes having the characteristicsotacid dyes by treating, in alkaline, solutioniwith an oxidizingagentfparticularly a'euprie oxide alkaline coupling of3-amino-l-hydroxybenzene product of 3-amino-i-hydroxybenzene in whichinvention.

which may be monosubstituted in the amino group and has afree-4-position relative to the hydroxyl group, with a diazo compoundcontaining at least one sulfonic acid or carboxylic acid this" mannerthe azo dye is changed" in respect of its tint, and the fastness 0f .thedyeingswhich ityieldsis'improvedL i i ,According to theviewshithertoheld it must be supposed that these azo dyes, in so far asathey containno further, .chromophoric groups, 10311 be transposed into the:colorless triazoles ,(pseudo: azimides); thus, for instance, the dyesulfanilic "acid-azo-3-amino-l.-hydroxybenzene would be transposed inthefollowing"manner:-

especially useful for dyeing leather, 'onwliich they produce yellow tobrown'tint'si If, contrary to this invention, a 4-substitution thesubstituent is ""in th e"free ll-position to the hydroxyl, such asl-methyl-2-amino-4-hydroxybenzene, is used instead of the3-amino-1-hydroxybenzene having no substituentin d-position to thehydroxyl, tliereiarelobtainedin the coupling or 'd-h amxjy-azqayes wmcnon treatment with compounds" containing copper yiem sparingly solublereddish-c0ppercompounds of nfi'technical du t cw b ew n time instead orthe" 3m The following examples illustrate the invention, the parts beingby weightn? Example 1.-1'7.3 parts of l-aminobenzenelsulfonic acid arediazotized and coupled with a solution alkaline with sodium carbonate of10.9 parts; of B-aminod-hydroxybenzene.y whenz cou m ne om i t r d dab u25mm of calcined sodium icarbonatez The rwholeis bi usht; to oi in a dema eous so ut on r 59 group, lending solubility, said dyes containing nogroup ;capab1e-,.of forming a metal complex: In

parts of crystallized copper sulfate is run in.; Afton iling for ashorttime the mass is filtered, while" filtrate. s V I p i "Whereas'theiisolutiori of theparent dye alkaline with sodium carbonate has anorange-brown tint,

that fof, theconversion product is a dull greenyellow. Thejdye dyeschrome-leather yellowbrown tints} the dyeing is essentially fastertolight'thanfthat of the parent dye.

QLIff instead of l-aminobenzene-4-sulfonic acid thereiare used 21,8parts of 4-nitro-1-amino-. benzene-2-sulfonic acid, there is obtaineda-dyewhich dyes chrome leather "golden-yellow.

,QInstadIOi 50 parts'of crystallized copper sulfate there may be used,for example, 12 parts of hotfia' nd the dye is salted out from thehydrogen peroxide of 30 per cent strength in the res nce some cupricoxide as a catalyst. Instead' of copper sulfate and; sodium carbonatethere maybeused the equivalent quantity of an ammoniacal solution ofcupric oxide.

from 11.3 partsof ,1 -aminobenzene-4-sulfonicacid is. allowed ,toflow,together; with a solution of '7 parts'of ,sodium hydroxide, into asolution of 18.5 partspf 3-hydroxydiphenylamine in 750 parts of waterand Sparts'of sodium hydroxide at about 201 C. When coupling: iscomplete, 25 parts of sodiumqcarbonate are added, the wholeis heatedtoboiling and there is then added a solution of 5 0- p,arts iofcrystallized, copper. sulfate. After boiling ionabout V hour thesolution isfiltered and the dyeqsalted outsfrom the filtrate, after thishas been neutralized with hydrochloric acid. Thedye dyes chrome, leatheryellow-brown tints, which arejessentially faster to light than thedyeing obtained withthe parent dye. ,I h Exqmple 3 ..35.'7,,parts; of4+aminoazobenzene- 3Af-disulfonic acid are diazotized in known man-' nerandjcoupled with a solution, alkaline with V are used 12.3 parts of1-methy1-4-amino-2-hy-- droxybenzene there is obtained a-dyewhich dyesleather somewhat redder tints.

Example 5.2l.8 parts of 4-nitrol-amino benzene-Z-sulfonic acid arediazotized in known manner and coupled with a solution alkaline withsodium carbonate of 10.9 parts of'1-hydroxy-3-' aminobenzene. mixture isheated to 80 C. andthe nitro group is reduced by stirring the mixturefor about an hour with 16 parts-of sodium sulfide, whereby the reddishyellow color changes to orange red. The reduced dye is separated byadding common salt' and hydrochloric acid. After filter pressing the dyeis'dissol'ved in 1000 parts of water with the addition of-ZO parts ofsodium carbonate, whereupon, afterheatingtq boiling, a'solution'of 40"parts of crystallized copper sulfate is run in.,

After stirring for a short time the conversion of the "dye is complete,the'tint having passed from orange to yellowbrown; *The dye isseparated. by filtering the precipitated oxide of copper and salting outin the usual manner." It dyes chrome leather and vegetable tannedleather reddish wn- I The same final product is obtained if a solu- 'onof cupric'oxide in ammonia is used instead of'th'ecopper sulfate."

, Example (ix-3255' partsof theacid sodium salt of 2-aininon'aphthalene.8-disulfonic acid are diazotized irr-the us'ualmanner and coupled witha. solution alkaline with sodium carbonate of 10.9 parts ofl-hydroxy-3-aminobenzene. r When coupling is complete, the mixture isheated toboiling and a solution of -55 parts of crystallized coppersulfate is run in in the presence of sodium carbonate in excess. Afterboiling for about 1 hour; the conversion oft-hedye istcomplete, the tinthaving. passedfrom reddish yellow to orange brown. -.1Afterfiltering thesolution and partially neutralizing the sodium carbonate in- -excess byaddition of hydrochloric acid,-the dye issepara'ted I in the usualmanner. It dyes-chrome leather Y dium carbonate;

and vegetable tanned leather clear yellowish brown tints; 1 .Whencarrying" out the oxidation with cupri tetrammonium sulfate, likewise, abrown dye-is obtainedshowing, however, a somewhat violet browntintiEmample-.7.."3;9 parts of2-amino=-8-hydroxynaphthalene-fiesulfonie. acid'are'diazotized in the known manner. wThe diazo compound is allowed torun into a solution of 1019' parts of I- hydroxy '3-amincbenzenei and 10Lpartsi' of anhydrous so- Y When coupling is complete, the mixture is'hea-ted' to boiling and a solution of 55 parts. of crystallized coppersulfate is' run in. Afterboiling for some hours, the mixture is filteredand the dye is separated from'the filtrate byfaddition'of common salt.The tint of the dye, likewise, has become essentially browner by thetreatment with copper oxide. It dyes chrome leather and vegetable tannedleather-clear reddish When coupling is complete, the

Summarizing, the new dyes are obtainable by oxidizing as set forth inthe foregoing examples an azo dye of the general formula wherein R isthe radicle of a diazo compound containing at least one sulfonic acid orcarboxylic alkoxy. These dyes shall not contain groups capable offorming a metal complex compound,

namely OH, -COOH, O-alkyl, in orthoposition to the azo group. All thesepossibilities of substitution are considered to be within the spirit ofthe invention and the scope of the following claims.

What I claim is:

'I. The process which comprises heating an azo dye of thegeneral formulaNHX heating an wherein R is a sulfo compound of the benzene "series, Xis hydrogen or a radicle of the benzene series, said initial dye beingin the ortho position. to the azogroup free from groups. capable offormingv av metal. complex, in an. alkaline medium. with hydrogenperoxide in the presence of a copper compound;

f1? The process which comprises heating. an. azo dye of the generalformula wherein R- is a sulfo compound of the benzene series; X ishydrogen or a radicle' or the benzene series, in an alkaline medium witha cupric oxide compound.

4. The process whichcomprises heating an azo dye of the general formulaNHX wherein R is a sulfocompound of the benzene series, X is hydrogen ora radicl'e of the benzene series, in an alkaline medium with hydrogen:peroxide in thepresence of a copper compound.

5. The process which comprises heating an azo dye of the general formulawherein R is a sulfo compound of the benzene series, in an alkalinemedium with a cupric oxide compound.

6. The process which comprises heating the dye corresponding to theformula M E M OH in an alkaline medium with a cupric oxide compound.

7. The process which comprises heating the dye corresponding to theformula in an alkaline medium with a cupric oxide compound.

8. The process which comprises heating the dye corresponding to theformula N=NQOH l in an alkaline medium with a cupric oxide compound.

9. The dyes dyeing leather from an acid bath yellow to brown tints ofgood fastness and being obtainable by the process set forth in claim 1.

10. The dyes dyeing leather from an acid bath yellow to brown tints ofgood fastness and being obtainable by the process set forth in claim 3.

11. The dyes dyeing leather from an acid bath yellow to brown tints ofgood fastness and being obtainable by the process set forth in claim 5.

12. The dye dyeing leather from an acid bath brown tints of goodfastness and being obtainable by the process set forth in claim 6.

13. The dye dyeing leather from an acid bath copper red tints of goodfastness and being obtainable by the process set forth in claim '7.

14. The dye dyeing leather from an acid bath yellowish brown tints ofgood fastness and being obainable by the process set forth in claim 8.

WERNER LANGE.

